The invention relates to improvements in powered airships, and more particularly to a powered airship having a flexible envelope inflated and superpressurized by hot air and capable of directed flight for transporting loads over distances and to an improved method and means for pressurizing the hull envelope.
Airships of this type have been referred to as dirigibles and originally referred to as blimps when the airship is nonrigid. The present invention in particular relates to a hot air inflated airship of the nonrigid pressure type. The main envelope or pressure hull is formed of a fabric such as a laminated plastic and Dacron, or of suitable other material which is lightweight, high temperature resistant, extremely strong and impermeable to gas leakage. The envelope of the airship is horizontally elongate and is primarily symmetrical with load lines distributed over the body of the envelope for carrying a payload therebelow.
The plastic fabric envelope when not in use can be folded and shipped or stored in the space which takes up less than 1% of its inflated volume. The envelope can be relatively rapidly inflated by the operation of a fan and the free lift is controllable by control of a burner which controls the temperature of the air within the envelope. The direction of flight is controlled by tail fins at the aft end of the airship envelope. These tail surfaces preferably include a rigid or stable portion which stabilizes the airship in horizontal flight, and a manipulable portion which changes the direction of flight. Vertically extending control surfaces are pivoted to the left or right to change the direction of flight, and horizontally extending surfaces move up or down to cause the airship to ascend or descend. Primarily, the temperature of the hot air within the airship is controlled to provide sufficient lift for the weight of the envelope and the payload being carried so that essentially free lift is present while the airship is in flight, and it ascends or descends in accordance with the change in angle of the control tail surfaces.
The features of the present invention relate particularly to an improvement for maintaining the airship envelope under a superpressure so that the skin of the envelope will remain essentially taut, and the envelope will retain its aerodynamic shape during flight. The mechanism for superpressurizing the envelope is so constructed to heat the air which enters the envelope and maintain heat within the envelope so as to provide adequate free lift for carrying the envelope and its controls with its payload. The arrangement is unique in that it employs a blower arrangement integrally constructed with a burner which act together as a system and provide an integral part of the airship itself. The arrangement provides for better heat distribution throughout the total air volume within the envelope, and because of the reliable superpressurizing inflation capabilities, it is possible to provide an envelope of soft material which has a semi-rigid to rigid shape and which eliminates the need for any external or internal supportive structure. This will also substantially lessen the aerodynamic drag forces encountered when moving this semi-rigid shape through the air. The integral arrangement eliminates the need for any outside or remote blowers to provide air for initial inflation of the envelope, and when the airship is ready for take-off or when stored, initial inflation to bring it to flying shape is accomplished by the same equipment which maintains the free lift within the envelope during flight.
In accordance with the invention, the burner is mounted directly in the airstream of the blower enabling it to heat the air passing into the envelope. The burner is so constructed so as to provide a sufficient heat level of the air already inside the envelope in order to maintain the required lifting ability. For reliability and rigidity, a unique support system is provided for attachment of the gondola to the airship envelope, and the blower is permanently mounted to the gondola making it an extension of the gondola superstructure. The blower is driven by its own power source which is located in the gondola immediately available to the operator therein. The interconnection between the gondola and envelope are such that the blower and burner are completely enclosed by the envelope and gondola of the airship and not subjected to external weather conditions or temperatures.
It is accordingly an object of the present invention to provide an improved method and mechanism for initially inflating an airship formed of an envelope of soft material and for also maintaining the inflation of the envelope during flight so as to provide a semi-rigid or rigid aerodynamically shaped flight structure.
A further object of the invention is to provide a unique relationship between the gondola airship envelope and inflation and air heating mechanism which is completely reliable in flight, readily accessible for control and tension during flight and so constructed as to not interfere with the aerodynamic capabilities of the airship.
Another object of the invention is to provide a unique blower and burner arrangement for heating the incoming air which is directed into the hull envelope and for maintaining the proper temperature of the air therein during flight.
Other objects, advantages and features, as well as equivalent structures and methods which are intended to be covered herein, will become more apparent with the disclosure of the preferred embodiments in connection with the teaching of the principles of the invention, as described and shown in the specification, claims and drawings, in which: